Conventionally, a chassis of an electric motorcycle has been known, which accommodates an electric component, such as a battery, or the like, which requires a relatively-wide mounting space (see Japanese Patent Application Publication No. 2006-219081). The chassis disclosed in Japanese Patent Application Publication No. 2006-219081 is provided with a mounting space defined by left and right half-frame parts and having on the lateral side thereof an opening through which the mounting space is exposed to the outside. Electric components are mounted into the mounting space through the opening in a state of being stored in an expandable accommodating casing. When the electric component is mounted, through the opening on the half-frame part, into the mounting space in a state of being stored in the accommodating casing, which is larger than the opening, it is possible to insert the accommodating casing into the mounting space of the chassis by making the accommodating casing contracted.
Main components, such as an electric motor, an inverter, a controller, and the like, are mounted in the chassis of an electric motorcycle. Since heavy current flows through such components, components are connected together by means of thick high voltage cables, which are, however, uneasy to mount. Further, since the electric motorcycle is provided with a plurality of sensors and switches, and a main harness has a complicated structure, the electrical wirings are complicated. Furthermore, currently-available electric motorcycles are required to be made lighter and smaller, so it is expected that, in the future, the mounting space in the chassis be reduced. Because of this, in the above-mentioned chassis structure in which electric components are to be mounted in a state of left and right half-frame parts being bonded together to form the chassis structure, it is difficult to mount the wirings.
Conventionally, a scooter-type electric motorcycle includes an electric motor on the side of a rear wheel attached to a rear swing arm connected to a chassis framework (see Japanese Patent Application Publication No. 2013-154859). In the electric motorcycle disclosed in Japanese Patent Application Publication No. 2013-154859, a pivot plate is provided onto a chassis framework, and a rear swing arm is connected such that it is vertically movable about a pivot axis of the pivot plate. Further, a side kickstand is attached to the pivot plate below the pivot axis. When the side kickstand flips down and makes contact with the ground, the electric motorcycle is kept upright for itself. Like this, for the scooter-type electric motorcycle, the attachment position of the side kickstand is separated from the electric motor.
For other type electric motorcycles, however, the electric motor is supported at a position in proximity to a pivot of the chassis framework. In order to allow the electric motor to be supported by the chassis framework, it is required to support an output shaft of the electric motor at three or more points around the output shaft so as to counteract a reaction against a driving force applied to the output shaft. Because of this, a problem arises in that the electric motor cannot be stably supported unless a section is used to support the electric motor throughout a wide lateral side area of the chassis framework.
Further, a bracket for a side kickstand is attached to the chassis framework in proximity to the support position of the electric motor. This bracket is formed from a forged material harder than the chassis framework, since it is subjected to a local load at a position close to a rotary shaft of the side kickstand. Therefore, since the chassis framework should include the attachment position of the bracket for a side kickstand, the chassis framework has a limited area to support the electric motor.